Particle detection apparatus



W. H. KINARDv PARTICLE DETECTION APPARATUS Filed DeC- 21, 1959 EEEEWIll: vIll:fifilllnllllnlllllllllrlflllrlfllllillflllll INVENTOR WILLIAMH KINARD ATTOEYS United StatesPatent 3,094,115*if H 1 PARTICLE DETECTIONAPPARATUS William H. Kinard, Newport News, Va., assignor'to the UnitedStates of America as represented by the Admmistrator of NationalAeronautics and Space Administration l Filed Dec. 21, 1959, Ser. No.861,152

l14 Claims. (Cl. 244-14) l (Granted under Title 35, UJS. Code (1952),sec. 266) The invention described herein may be manufactured and used byor for the Government of the United States of America for governmentalpurposes without the payment of any royalities thereon or therefor.

This invention relatesgenerally to particle detectors, and moreparticularly to detector apparatus for indicating the frequency ofincidence and energy of minute space particles.

iIn space craft intended for orbital or interplanetary flight, it isnecessary for the skin thereof to be capable of withstanding collisionswith minute space particles, such for example as micro-meteorites, orthe like, to protect the instruments and/or occupants carried by thespace craft. In order to insure the adequacy of the skin, or shell,structure, it is desirable that the design thereof be based uponinformation indicative of the collision conditions likely to beencountered by the space craft, orvehicle.

Although particle collisionedetectiageevieesehave beeae;eareactedefeaaeeatral plaaaesectien'ls'eonpesedeefaev other objects areattained bythe provision of an erectable and insulating' materials, acommon source of potential energy, a common indicating device, and anelectrical impedance individually coupling each of the conductive layersto the energy source and indicator.

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered'in connection with the accompanying drawing wherein:

FIG. l is a side elevational view of the aerospace particle detector inits fully extended and operational condition;

FIG. 2 is Ian enlarged view, partially in section, of the electricalcircuitry utilized in the present invention; and,

FIG. 3 is Ia side elevational view, partially in section, of theaerospace particle detector in its stored for launching condition.

Referring now to the drawing, wherein like reference numerals designateidentical or corresponring parts throughout the several views, and moreparticularly to `FIGS.'1 and 2, the particle vdetector apparatusaccording to the' instant invention is shown as consisting essentiallyof ra data recording system 11 shock-mounted in a nose cone 12 and yatarget body 13 capable of being towed behind the nose cone. The targetbody, or sail, 13 is conheretofore devised and utilized, in general,these prior art eral superposed :thin sheets of laminated material, and

detection device provides for the disposition of a microphone andcounter within the casing of the space vehicle. The microphone providesa signal to the counter in rcsponseto the acoustic noise generated byeach particle collision with the vehicle casing. Although this lattersystem overcomes the aforementioned shortcoming of the former system,neitherof these prior art arrangements are capable of providing ameasurement ofthe energy content of the colliding particle.

An object of this invention is therefore to provide a new and improvedapparatus for determining the'incidence and energy Vcontent of minuteparticles.

Another object of the instant invention is the provisionV of a new andimproved electrical system for accur-ately counting the frequency ofoccurrence of small-sized solid particles.

Still another object of the present invention is the provision of a newand improved electrical system for accurately indicating the magnitudeof momentum of smallsized solid particles.

A further object of this invention is to provide a novel towableaerospace target selectively responsive tothe impiugement of minuteparticles of matter.

Vpact packaged condition and of being erected to a* fully extendedcondition.

According to the present invention, the foregoing and interconnectedperipheral and diagonal tubuluar channels 15 -adhesively secured theretoas at 16. The laminated sheets are formed of -a base layer 17 oftensionally strong and flexible insulating material, such for example asthe polyester Mylan to which is secured -a layer 18 of lightweight andbendable electrically conductive material, such for example as aluminum.The aluminum may be secured to the base layer by the use of an adhesiveor by a conventional metal depositing process. The tubular channels 15may be formedrof rubber, parachute cloth, or the like, but Mylar is apreferred material. A pair of valves 19 are provided in a forwardtubular channel through which an iniiatng medium, such for example' ascompressed air, or a plastic foam, such for example as a polyester, isintroduced for distribution to all of the channels 15 thereby impartinga degree of rigidity thereto and full extension of the target sail 13.The inating or stiffening medium may Vbe'applied to the valves 19through a hose-like tow line Y20 connected to a storage container 21positioned within the nose cone 12. The tow line is preferably inthreaded engagement with the valves 19V and container 21. To minimizethe likelihood of bucklingof the target sail, one or more diagonalchannels also may be formed thereon. It will be apparent to one skilledin the art that byV reason of the lightweight structural nature of thetarget body 13, a substantially large sized sail can be deployed forsampling a greater spatial area thereby increasing the statisticalaccuracy of the data obtained.

As more clearly shown in FIG. 2, the data recording system 11 utilizedin the present invention consists of an electrical energy source, suchfor example as a charged condenser 22, one plate of which iselectrically coupled through conductor 23 to an outermost aluminum layer18 ofthe target sail, and the other plate of whichis eleceV tricallycoupled throughV conductor 24 to a load impedance, such for example as aresistance 25. Each of the remaining aluminum layers 18 is coupledthrough an individual conductor 26 of an electrical cable 27 to in-Yminiature sized telemetering transmitter 32 is parallel coupled to thecommon load resistance 25.

vPrior to assuming the fully extended and operational conditionillustrated in PIG; 1, the target sail 13 is carried aloft in a`collapsed. and compactly folded condition within an open endedcontainer 33 formed inthe after portion of the nose cone 12 of alaunchingvvehicle, or rocket, 34, as shown in. FIG. 3.2 The nose cone.12 is secured'to the propellant motor'BS byV conventional means, notshown. When the-rocket. 3.4. has reached the desired altitude at whichit is desired to deploy the target sail, as

may bev determined. by a conventional4 altimcter, or timing. mechanism36,:the nose. conev Lzfis. detached from the motor-'35 by conventionalmeans, not shown.` Upon separation ot the noseV cone 12, theA collapsedtarget sail 13 is ejected from its container 33 by conventional means,such for example as a Ycompressed spring 37. Flow of the inliatingmedium from storage container 21 will then be initiated through towingconduit v and unfolding o the target sail Vuntil fully extended willresult. L

In operation, an impinging space particle 38; will penetrate the targetsail 13y toA a depth proportionateVA to the level ot momentum thereof,as shown in- FIG. 2;. The

v penetration'of each layer will he attended by thev release,

in the small. immediate area, of la. high level of energy, which issumcient to successviely vapon'ze the nearby target materials andthenmionize the resultant vapor. Thus, as the particle penetrates. thevstacked. array of laminated sheets. of the central sailfportion 14,.ionization oi each layer of almninum penetrated will occur, therebyeffectively producing a. short circuit path between adja cent penetratedaluminum layers 18. As successive adjacent aluminum sheets become shortcircuited, successive ones of resistors 28 will be placed in parallelwith one another in the discharge path of charged condenser 22.

vThe discharge time constant of the circuit will be'correspondinglyreduced with a consequent increase in the potential signal, or drop,across.A load resistor 25. Prior calibration of the potential signal`developed across. the

load resistance in response to the introduction of successive ones ofresistors 2.8 will allow for a measurement of the depth of penetrationof the colliding particles, from which data the momentum of theparticles can be readily determined. The potential signal across theload resistor is recorded by the recorder 31 and/ or suitablytransmitted by transmitter 32 to a remote receiving station. Inasmuch asthe ionization phenomenon is short lived; i.e., two milli-secondsduration, and with the exceeding rarity lof simultaneous particleimpingement, an accurate measurement of each particle collision and themomentum thereof will be obtained.

Whereas the operation of the device according toY the present inventionhas been described in connection with a missile, or rocket, nose cone,it is not so limited, and may also be used with equal advantage inconnection with aerial vehicles, suchy for example as aircraft, or thelike.

Obviously many modiiications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as. speciiically described.

What is claimed Ias new and desired to be secured by Letters Patent ofthe United States is:

l. A collapsible target comprising a planar section formed of alternatelayers of flexible and tensionally strong non-conductive material andlightweight and bend- `able metallic material, ya continuous enclosedchannel formed of tlexible and tensionally strong non-conductivematerial connected to the periphery of said planar section, andA meansfor introducing an inflating medium into said channel to elect erectionof the target.

2. A collapsible aerospace target. comprising a planar section formed ofsuperposed. alternate-layers of polyester material and aluminummaterial, a continuous tubular member formed. of polyester materialadhesively attached to said planar section alongthe entire peripherythereof, a valve positioned in said tubular member, andl means coupledto said valve for introducing an inflating medium into saidtubularmemher-to.- ecct. erection of the vaerospacetarget..

3. A collapsiblex aerospace target' according to claim- 2 and includingat least one tubular member diagonally attached to said planar sectionand formed; integrally withv said continuous tubular member. 4. Acollapsible aerospace target according to claim 3 wherein. saidintiating medium isaplastic foam.

5. A particle detection system vcomprising a `target formed ofsuperposed alternate layers of flexible vauditeusionally strong`nonconductive materiali-and` lightweight `and bendable metallicmaterial, a plurality of impedances,

each of which is individually coupled toone of; said ntie.-V talliclayers, an electrical energy source, coupled to. one

metallic layer, and means coupled betweeny said energy sourceA and saidpluralityy ofimpedances responsive to potential variations resultingfrom the momentary ionization of said metallic layers penetrated'byparticles: colliding with said target..

6. Arsystem according to claim 5: wherein said means comprises arecording device; Y

7. A system according to claim 5. .wherein said means comprises atransmitter.

8. A system according to claim 5 wherein said. e1ec .trical' energysource comprises a chargedV condenser.

9; An aerospace particle detection; system comprising a propelledvehicle, a target sail disposed in said vehicle inra collapsedcondition, said target sail being formed of alternate layers ofpolyester and aluminum materials, a continuous iiexible tube attached tothe periphery of said target sail, a container of an inllating mediumdisposed in saidfvehicle, a exible conduit coupled tosaid container andtoV said tube for towing said target sail behind said vehicle uponejection therefrom and for transmitting said inilatingmedium to saidtube thereby electngV erection of said target sail, circuit meansdisposed in said vehicle, said circuit means including an electricalenergy source coupled tov one of said aluminum layers, a plurality ofimpcdances, each of which is individually coupled to one -of saidaluminum layers, and means coupled between said energy source and all ofsaid plurality of impedances responsive to energy flow variations insaid circuit means resulting from the momentary ionization of saidaluminum layers penetrated by particles colliding with said target sail.

l0. Au aerospace system according to claim 9y wherein said meanscomprises a recording device. A

ll. An aerospace system according to claim 9 wherein said meanscomprises a transmitter.

12. An aerospace system according to claim 9 wherein said meanscomprises a recording device and a transmitter.

13. An aerospace system according to claim 9 wherein said electricalenergy source comprises a charged condenser.

14. A particle detection system comprising a target -formed ofsuperposed alternate layers of nonconductive material and metallicmaterial, a plurality of impedances, each of which is connected to. oneof said metallic layers, an electrical energy source connected to onemetallic layer, and means coupled to said energy source and to saidplurality of impedances for responding to potential variations resultingfrom the momentary ionization of said metallic Vlayers penetrated byparticles colliding with said target.

References Cited in the tile of this patent UNITED STATES PATENTS

